Method and apparatus for processing signals of a spherical microphone array on a rigid sphere used for generating an ambisonics representation of the sound field

US9503818B2 · kind B2 · utility

Assignee

• Dolby Laboratories Licensing Corporation · US

Inventors

• Sven Kordon · Wunstorf, DE
• Johann-Markus Batke · Hannover, DE
• Alexander Krueger · Burgdorf, DE

Key dates

• Filing date: Oct 31, 2012
• Grant date: Nov 22, 2016
• Expiry date: Oct 31, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04S2400/15
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

Spherical microphone arrays capture a three-dimensional sound field (P(Ωct)) for generating an Ambisonics representation (Anm(t)), where the pressure distribution on the surface of the sphere is sampled by the capsules of the array. The impact of the microphones on the captured sound field is removed using the inverse microphone transfer function. The equalization of the transfer function of the microphone array is a big problem because the reciprocal of the transfer function causes high gains for small values in the transfer function and these small values are affected by transducer noise. The present principles minimize that noise by using a Wiener filter processing (34) in the frequency domain, which processing is automatically controlled (33) per wave number by the signal-to-noise ratio of the microphone array.